﻿Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginHandler);
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndHandler);

function BeginHandler(sender, args) {
  $.blockUI({
    message: '<div style="font-size: 30px;padding: 20px;">Aguarde...</div>'
  });
}

function EndHandler(sender, args) {
  $.unblockUI();
}